Blast actuated safety for rocket launchers



Feb. 15, 1955 M. T. SMITH BLAST ACTUATED SAFETY FOR ROCKET LAUNCHERS Filed April 20 1951 'IIIII) IIIII/IIIII/ I 1 1/1 I IIIIIIIIII/II/I/ [III III III m it I! I A "BEEF I II I x x 34 3f;

INVENTOR.

Mtu ahull Tl Smil'h ATTORNEYS 2,701,9li BLAST ACTUATED SAFETY F032 RUWT The invention described in the specification and claimsmay be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to a safety device for rocket launchers of the recoilless type and more particularly to a safety device operated by the blast of a rocket fired from the launcher.

Many of the rockets now in military are fired electrically by means of squib located in the rocket. The launcher for such a missile contains firing circuit completed by the squib and adapted to sari electrical impulses to the rocket. If the launcher it is closed constantly, a rocket may be inserted, conr etc the circuit and be fired prematurely, the blast of the projectile ofierg possibility of serious injury to the operator. Firing circuitsin use at present sometimes contain hand operated safety switches. Failure of the operator however to open these switches nullifies their value. it is therefore a primary objective'of this invention to provide an automatically operated safety switchior rocket launchers. One factor common to all rockets is the blast of hot gases emitted by each when fired. A second object of the invention is provision of a safety for rocket launchers automatically operated by the blast of hot gases emitted by the rocket when fired. objects of the invention will be evident hereinafter.

In broad outline my invention is a switch, mechanically actuated by the rocket blast, which automatically opens the firing circuit of the launcher each time a rocket is fired. A moving part of the switch, actually contacted by the hot gases, is physically of such dimensions that it will prevent loading of the launcher as long as this part is in position to be actuated by the blast. Details of the invention may be seen from the drawings in which: I I

Figure l'is a longitudinal section of the breach end of a rocket launcher tube showing our invention and part of a rocket in the firing position;

Figure 2 is an enlarged view of vane or moving [part of my switch; a

Figure 3 is an enlarged View of my invention as shown in Figure l, the dotted lines showing the safety in the loading position; 5

Figure 4 is a view of the mventlon seen rrom above; and

Figure 5 is a diagram of the thing circuit of a conventional launcher showing my invention in the closed or firing position.

' Referring in detail to the drawings, a conventional rocket launcher tube 20 is shown with a support 24 "mounted on .the upper part of its breech portion 22. Extending down over this exit 22 is an actuating arm 28 pivoted on support 24 on an axis transversely of the axis of the tube." A blast vane 36 is integrally connected with one end of arm 28. This vane serves to partially close or obstruct the breech 23 when the launcher is ready to fire. At its end opposite the vane arm 28 carries a pin 32 joining it to connecting rod 34. Rod 34 has a projection 36 integral therewith and a coupling 38. The coupling 38 is fastened directly to a positive positioningpush-pull electrical swltch d0 of conventional design. Q E

Switch 40 is in series in the tiring circuit or rocket launcher 20. Wires 42 and 44 are the firing leads connecting the switch in the circuit. Wire ift is joined to trigger 26.- This trigger is of known design and conmeans of handle 46.

I greases tains a small magneto witch 48 is an operator controlled safety opening or closing the firing circuit. Wire 50 18 in series with wire 42 through the magneto and connects the trigger to contact 520:: the rocket launcher.

The circuit may be completed through'a rocket inserted in the tube, extending now through contacts so and 5%,

wires 60 and 62, and squib 64 in the. rocket to contact 56,

' insulated from the launcher itself. Contact 5d connects through wire 44 to one side of switch do, from the other sideof which extends wire 42.

The operation of my safety is evident from the drawrugs and the foregoing description.. When arm 2% is in the upyor loading position, shown in dotted lines in- Figure 3, a rocket can be inserted into the launcher. Movement of the arm 28 is transmitted through connectmg rod Q4 to switch 40, a simple push-pull switch. When arm 28 18 up switch is open, breaking the firing circuit of the launcher. Vane 30 is so large that as long as it is in position over the exit of the launcher tube the latter cannot'beloaded. Raising the arm of course breaks the firingcircult. Consequently it is impossible to load a rocket m place while the firing circuit is closed. The operator must clpse the firing circuit after the rocket is in place by pulling-back the arm 28 by means of the pro ecting handle 36. Pulling back on this projection moves the vane mto the blast path of a rocket in the launcher. When the arm has been pulled down, and

any other safety such as switchdb closed the rocket launcher is in the firing position. When the trigger is pulled the magneto sends an impulse through the squib and ignites the propellant. The hot gases formed as decomposit on products of the propellant create a blast which partially strikes the vane 30. The energy transferred to the flange is 's'ufiicient to force the arm up and into the open or dotted line position shown upon Figure 3. Thus the firing circuit is automatically broken each tmte a rocket 1s fired. It may be observed that vane 30 serves a dual purpose: (1) to open the safety switch when hit by the rocket blast; and (2.) to prevent insertion of a rocket when the safety switch is closed.

In the claims, the term trigger switch is to be interpreted as any means by which the firing circuit is ener gized by and in response to actuation of the trigger, when the safety switch is closed.

My safety is cheap, light, simple and easy vto construct. Yet it possesses the ruggedness to withstand severe military usage. That modifications are possible will be apparent to those skilled in the art. I wish therefore to be limited only by the scope of the appended claims.

I claim: v

1. In a breech-loading launcher for a rocket wherein the rocket is-loaded in an axial direction into the breech end of the launcher tube and has an electrical firing circuit including contacts in its side wall, a launcher tube, a firing circuit carried by said tube including a trigger switch and a safety switch in series, and electrical contacts engaging the contacts of the rocket when the latter is in firing position longitudinally within said tube, a blast vane carried by said tube for movement from a first position within the blast path of a rocket in firing position in said tube, to a second position free and clear of said path, and a connection between said vane and safety switch closing and opening said switch by and inresponse to movement of said vane to said first and second positions, respectively, said vane when in first position closing ried by said tube and including a trigger switch, a safety switch and a pair of spring-urged contacts engaging the respective contacts of the rocket when the latter is loaded to predetermined position longitudinally within said tube,

gnot shown) hand operated by of a rocket lannched from aromas i from a first position wherein it 18 free and clear of said'blast, and a mechanical connection response when insaid first position positively ing of a rocket into said tube and when moved from said first. position to said second position by the blast of the fired rocket actuating said safety switch to open position through said mechanical connection.

3. In a breech loading launcher for a rocket wherein therocket is loaded by movement in the direction of its longitudinal axis into the breech end of the launcher tube and has an electrical firing circuit mcludin a pan of insulated contact bands on its side wall, a auncher tube, circuit means carried by said tube and mcludmg a trigger switch, a pair of contacts engaging the respective bands of the rocket when the latter is loaded to predetermined firing' position longitudinally within said tube, and a safety switch, a 'blast vane mounted on said tube at the breech to movement of said.

a blast vane mounted to said tube for pivotal movement impinged by the blast said tube, to a second position.

-. said tube and end thereof for movement from a first position in and obstructing the path of loading of a rocket into said tube, to a second position free and clear ot sa1d path, and a manually operable mechanical connection between said vane and said safety switch to close and open the same by and in response to movement of sand vane nto first and second positions,-respect1vely, said vane being automatically moved to second position by the blast of a rocket launched from said tube and when moved from said first position to said second position by the blast of the fired rocket actuating said safety switch to open position through said mechanical connection 4. In a breech loading launcher for a rocltet which s loaded b motion in the direction of its longitudinal axis into the reech end of the launcher: tubeand has an electrical firing circuit including a pair of insulated contact .ing an operating member to o bands on its side wall, alauncher tube. aflring-tch, a safety switch carried externally by said tube and includd saignswitch, an ma g conwhen the rocket axially in said tube, 11 the breach and of vanefor pivotal movement about an M18 external-an H of said movement from, a first position infthe blast'path of a rocket loaded into-said .tube, to-a-second-position free and clear of said path, and and pivotallg vane and operating member to closean "en and safety in response to movement 0 tween first and second pen and close a pair of contacts fixed with said. tube tact with respective ones of saidbands is loaded into predetermined position a blast vane, racket means .fixed' mounting;

positions, said vane when in said first position only bstructing'sahlipath to positively w vent the loading of the rocket into, said tube and being moved to second en moved from said first tion to said second position by the blast of the fired actuating. said safety switch said mechanical connection.

References-flied in the iv 2:464:920 Cart .JIII Mar. 22', 1949 2,485,715 .Eastman on. 25, 1949 2,496,316 Skinner et a1. Feb. 7, 1950 2,517,333 Motley Aug. 1, 1950 2,557,151 Skinner et al. June 19, 1951 FOREIGN PATENTS 219,690 I Switzerland as. 1, i942 said vanebe.

4 position by the blast of the rocket when fired from said tube and wh 5.;

rocket o open posmon throng 

